Sprung coupling

ABSTRACT

A preassembled combination connects a captured pipe element to a second pipe element. First and second segments are connected end to end surrounding a central space for axially receiving the second pipe element. The segments are configured to be drawn toward one another and into engagement with the pipe elements. An annular body forms the captured pipe element. An end face of the captured pipe element is retained within the central space by engagement between a bead projecting from a sealing surface of the captured pipe element and the coupling assembly.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims benefit of priority toU.S. patent application Ser. No. 15/593,662, filed May 12, 2017 whichapplication is based upon and claims the benefit of priority to U.S.Provisional Application No. 62/336,879, filed May 16, 2016, and U.S.Provisional Application No. 62/336,885, filed May 16, 2016, all of theseapplications being hereby incorporated by reference.

FIELD OF THE INVENTION

This invention relates to mechanical pipe couplings for joining pipeelements.

BACKGROUND

Mechanical couplings for joining pipe elements together end-to-endcomprise interconnectable segments that are positionablecircumferentially surrounding the end portions of co-axially alignedpipe elements. The term “pipe element” is used herein to describe anypipe-like item or component having a pipe-like form. Pipe elementsinclude pipe stock, pipe fittings such as elbows, caps and tees as wellas fluid control components such as valves, reducers, strainers,restrictors, pressure regulators and the like.

Each mechanical coupling segment comprises a housing having projectionswhich extend inwardly from the housing and engage, for example, theouter surfaces of pipe elements of various configurations including, forexample, pipe elements having circumferential grooves. Engagementbetween the projections and the pipe elements provides mechanicalrestraint to the joint and ensures that the pipe elements remain coupledeven under high internal pressure and external forces. The housingsdefine an annular channel that receives a ring gasket or seal, typicallyan elastomeric ring which engages the ends of each pipe element andcooperates with the segments and the pipe elements to provide a fluidtight seal. The segments have connection members, typically in the formof lugs which project outwardly from the housings. The lugs are adaptedto receive fasteners, such as nuts and bolts, which are adjustablytightenable to draw the segments toward one another.

Mechanical couplings for grooved pipe elements according to the priorart have continuous arcuate projections on the segments that engage theouter surfaces of the pipe elements which they are joining end to end.These arcuate projections are part of the segment structure commonlyreferred to as the “keys” of the coupling. The keys may engage the outersurface of pipe element in various configurations including, forexample, pipe element having circumferential grooves.

The arcuate projections on prior art couplings for grooved pipe elementstypically have arcuate surfaces with a radius of curvature that ismarginally larger than the radius of curvature of the outer surface ofthe pipe element within the groove that it is intended to engage. Forcouplings used with grooved pipe elements, the radii of curvature of thearcuate surfaces are smaller than the radii of curvature of the outersurfaces of the pipe elements outside of the grooves so that theprojections fit within and engage the grooves.

Methods of securing pipe elements in end to end relation comprise asequential installation process when mechanical couplings according tothe prior art are used. Typically, the coupling is received by thetechnician with the segments bolted together and the ring gasketcaptured within the segments' channels. The technician firstdisassembles the coupling by unbolting it, removes the ring gasket,lubricates it (if not pre-lubricated) and places it around the ends ofthe pipe elements to be joined. Installation of the ring gasket oftenrequires that it be lubricated and stretched to accommodate the pipeelements. With the ring gasket in place on both pipe elements, thesegments are then placed one at a time straddling the ends of the pipeelements and capturing the ring gasket against them. During placement,the segments engage the gasket, the projections are aligned with thegrooves, the bolts are inserted through the lugs, the nuts are threadedonto the bolts and tightened, drawing the coupling segments toward oneanother, compressing the gasket and engaging the projections within thegrooves.

As evident from the previous description, installation of mechanicalpipe couplings according to the prior art requires that the techniciantypically handle at least seven individual piece parts (and more whenthe coupling has more than two segments), and must totally disassembleand reassemble the coupling. Significant time, effort and expense wouldbe saved if the technician could install a mechanical pipe couplingwithout first totally disassembling it and then reassembling it, pieceby piece.

SUMMARY

The invention concerns a preassembled combination for connecting acaptured pipe element to a second pipe element. In one exampleembodiment the captured pipe element defines an axis and the combinationcomprises a coupling assembly comprising first and second segmentsconnected end to end such that first and second ends of the firstsegment are connected to first and second ends, respectively, of thesecond segment, such that the first and second segments surround acentral space for axially receiving the second pipe element. The firstand second segments are shaped and configured to be drawn toward oneanother and into engagement with the pipe elements. First and secondshoulders are positioned on opposite sides of each of the segments. Theshoulders of the segments extend along the segments and projectradially-inwardly toward the central space. A first arcuate surface ispositioned on and extends along each of the first shoulders. The firstarcuate surface has two ends and a midpoint therebetween. A secondarcuate surface is positioned on and extends along each of the secondshoulders of the first and second arcuate surfaces facing the centralspace. A channel is positioned between the first and second shoulders ineach of the segments. The channels extend between the ends of thesegments and facing the central space. An annular ring seal ispositioned within the channels. The ring seal has inner surfaces sizedto receive the pipe elements. The ring seal supports the segments inspaced apart relation sufficient to permit insertion of the second pipeelement into the central space while the segments are attached to oneanother. The captured pipe element comprises an annular body. Theannular body has an end face located within the central space. A sealingsurface extends around the captured pipe element for engagement with theinner surface of the ring seal. A bead projects outwardly from thesealing surface and extends circumferentially therearound. A groove isaxially spaced from the end face. The groove engages with the firstarcuate surfaces of the first shoulders of the segments. A pipe shoulderis positioned distal from the end face and adjacent to the groove. Theend face of the captured pipe element is retained within the centralspace by engagement between the bead and the coupling assembly.

In an example embodiment of a combination according to the invention,the end face of the captured pipe element is retained within the centralspace by engagement between one of the bead and the pipe shoulder withthe coupling assembly. Further by way of example, the bead is positionedin spaced relation to an end of the captured pipe element. Also by wayof example, the sealing surface is positioned between the end and thebead.

In an example combination according to the invention the couplingcomprises an adjustable attachment assembly adapted to draw teh firstand second segments toward one another and into engagement with the pipeelements. By way of example the adjustable attachment assembly comprisesa first lug attached to the second end of the first segment. A secondlug is attached to the second end of the second segment and ispositioned in facing relation with the first lug. Each lug defines arespective hole. A fastener extends between the first and second lugs.The fastener is received within the respective holes. The fastener isadjustable for drawing the segments toward one another.

In a further example combination the inner surfaces of the annular ringseal have an innermost extent located at a first radial distance fromthe axis when undeformed. The segments are supported such that themidpoints of the first arcuate surfaces are supported at a second radialdistance from the axis. An outermost portion of the bead is located athird radial distance from the axis. The third radial distance isgreater than the first radial distance in an example embodiment.

In a further example combination according to the invention the innersurfaces of the annular ring seal has an innermost extent located at afirst radial distance from the axis when undeformed. The segments aresupported such that the midpoints of the first arcuate surfaces aresupported at a second radial distance from the axis. The third radialdistance of the bead is greater than the second radial distance of themidpoint of the first arcuate surfaces.

In an example combination the bead is engaged with the ring seal. By wayof example, engagement between the bead and the ring seal createsinterference that impedes movement of the captured pipe element in afirst direction along the axis of the ring seal.

By way of example, in a combination according to the invention,interference between the pipe shoulder and the coupling acts to limitmovement of the captured pipe element along the axis of the ring seal.

In an example combination according to the invention the captured pipeelement is retained within the central space such that the firstshoulder of the coupling assembly is located axially between the pipeshoulder and the bead.

In an example embodiment a first pipe element is shaped and configuredfor engagement with a coupling for joining together the first pipeelement and a second pipe element. By way of example the couplingcomprises a plurality of segments attached to one another end to end toform a loop around a central space. Each of the segments comprises afirst shoulder, a second shoulder, and a channel disposed between thefirst and second shoulders and facing the central space. The first andsecond shoulders project radially-inwardly toward the central space. Aflexible, resilient ring seal is positioned in the channels. The ringseal comprises first and second lobes that each extend radially inwardlyto define first and second ring inner seal surfaces, respectively. In anexample embodiment the first pipe element comprises a first end, acircumferentially extending sealing surface, an annular groove, a pipeshoulder extending radially-outwardly, and a bead extendingradially-outwardly. In an example the bead, annular groove, and sealingsurface are all axially disposed between the first end and the pipeshoulder, the bead and sealing surface are both axially disposed betweenthe annular groove and the first end, the first pipe element is shapedand configured to be preassembled with the coupling to form apreassembled combination in which (1) the first end and pipe shoulderare positioned within the central space, (2) the coupling ispreassembled such that its segments are attached to one another end toend to form the loop around the central space, (3) the bead extendsradially outwardly farther than an inner radial extent of the firstlobe, (4) the coupling and bead are shaped and positioned such that thefirst and bead are captured within the central space such that the firstpipe element is captured by the preassembled coupling, (5) the secondshoulders of the plurality of segments are axially disposed between thebead and pipe shoulder and are axially aligned with the annular groove,and (6) an end of the second pipe element may be axially inserted intothe central space. The first pipe element is shaped and configured suchthat when the first pipe element and coupling form the preassembledcombination and the end of the second pipe element is properly insertedinto the central space, the plurality of segments can be drawn towardone another and the central space and to thereby cause (1) the firstring inner seal surface to sealingly engage the sealing surface of thefirst pipe element, (2) the second ring inner seal surface to sealinglyengage a sealing surface of the second pipe element, (3) the secondshoulders of the segments to engage the groove of the first pipeelement, and (4) the first shoulders of the segments to engage anannular groove of the second pipe element, thereby joining the secondpipe element with the first pipe element.

By way of a further example combination with the ring seal, the firstend and bead of the first pipe element are disposed within a centralopening formed by the ring seal, the bead extends radially outwardlyfarther than an inner radial extent of the first lobe and engages thefirst lobe. Engagement between the bead and the first lobe createsinterference that impedes axial movement of the ring seal relative tothe first pipe element in a first axial direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of an example embodiment of a pipe couplingaccording to the invention;

FIG. 1A is an isometric view of a portion of the example pipe couplingshown in FIG. 1;

FIG. 2 is an axial view of the example pipe coupling shown in FIG. 1;

FIG. 3 is a sectional view of the example pipe coupling shown in FIG. 1;

FIG. 4 is a partial sectional view of the example pipe coupling shown inFIG. 1;

FIG. 5 is an isometric view of a component used in an example coupling;

FIG. 6 is a partial sectional view of the example pipe coupling shown inFIG. 1;

FIG. 7 is a sectional view of the example pipe coupling shown in FIG. 1;

FIG. 8 is an end view of the example pipe coupling shown in FIG. 1;

FIG. 9 is an exploded isometric view of an example preassembledcombination coupling and pipe element according to the invention;

FIG. 9A is an isometric view of the example combination of FIG. 9 shownin a preassembled state;

FIG. 9B is a sectional view of the example combination shown in FIG. 9;

FIG. 9C is an axial view of the example combination shown in FIG. 9;

FIGS. 10 and 11 are sectional views of the example combination shown inFIG. 9 illustrating assembly of a pipe joint; and

FIG. 12 is a sectional view of an example preassembled combinationcoupling and pipe element.

DETAILED DESCRIPTION

An example embodiment of a coupling 10 according to the invention isshown in FIGS. 1 and 1A. Coupling 10 is for joining pipe elements andcomprises first and second segments 12 and 14 positioned end to endsurrounding a central space 16 for receiving the pipe elements. A springassembly 18 joins a first end 20 of first segment 12 to a first end 22of the second segment 14. The spring assembly 18 biases the segments 12and 14 away from one another toward or into an open, pre-assembled stateshown. When in this open or pre-assembled state, pipe elements can beinserted into the central space 16 without disassembling the coupling 10as described below.

The example spring assembly 18 shown in FIGS. 1 and 2 comprises a firstboss 24 projecting from the first end 20 of the first segment 12, and asecond boss 26 projecting from the second end 22 of the second segment14. The second boss 26 is positioned adjacent to the first boss 24.Bosses 24 and 26 are cantilevers and thus are substantially responsiblefor the biasing force of the spring assembly 18 as described below. Afirst fulcrum 28 is positioned on the first boss 24, the first fulcrum28 contacting the second boss 26 and providing an axis 30 about whichthe segments 12 and 14 may pivot. In this example embodiment a secondfulcrum 32 is positioned on the second boss 26. The second fulcrum 32contacts the first fulcrum 28 to further define the pivot axis 30 aboutwhich the segments 12 and 14 pivot. First and second fulcrums 28 and 32are defined in this example embodiment by first and second lands 34 and36. The first and second lands 34 and 36 are respectively positioned onthe first and second bosses 24 and 26, the first land 34 beingcontiguous with the first fulcrum 28, and the second land 36 beingcontiguous with the second fulcrum 32 (when present). At least the firstland 34 is oriented angularly with respect to a plane 38 comprising theinterface between the first and second segments 12 and 14. In thisexample embodiment both the first and second lands 34 and 36 areangularly oriented with respective orientation angles 40.

A link 42 extends between the first and second bosses 24 and 26. Link 42captures the bosses, while permitting pivoting motion of the segments 12and 14. In this example the link 42 comprises a ring 44 which encirclesthe first and second bosses 24 and 26. Ring 44 is retained on the bosses24 and 26 by engagement with first and second heads 46 and 48respectively projecting from the first and second bosses 24 and 26. Ring44 and the bosses 24 and 26 cooperate to provide the spring biasingaction of the spring assembly 18. The thickness 50 of the ring 44, thedistance 52 between the fulcrums 28 and 32 and the point where thebosses 24 and 26 engage the ring 44, along with the area moment ofinertia of the bosses, are parameters which will establish the springconstant of the spring assembly 18 and thus determine the amount offorce necessary to close the coupling 10 and effect a joint. The angularorientation 40 of the lands 34 and 36 and the distance the fastener 70has been tightened each act to set the maximum limit of separationbetween the segments 12 and 14, and the inner diameter 54 of the ring 44determines the minimum separation of the segments when supported by anundeformed spring assembly 18 as shown in FIGS. 1 and 2. In oneembodiment, the angular orientation 40 is such that, if the fastener 70is not present (such as during the assembly of the coupling by themanufacturer) bosses 24, 26 may be brought near enough together that theinner diameter 54 of ring 44 will clear heads 46, 48, allowing ring 44to be easily assembled over bosses 24, 26. Subsequent assembly andtightening of fastener 70 to a pre-determined distance 71 (see FIG. 2)acts to separate heads 46, 48 sufficient to retain ring 44 behind heads46 and 58 as described above. The ring inner diameter 54 may be sized tohold the segments 12 and 14 in the open or pre-assembled statesufficient to permit insertion of pipe elements into the central space16, or the diameter 54 may be larger, and permit the segments 12 and 14to be supported in the open or pre-assembled state by other elements ofthe coupling as described below. In this situation the segments 12 and14 will have some angular free play as the segments are drawn toward oneanother to close the coupling, the spring assembly 18 not immediatelycoming into effect upon pivoting of the segments.

Segments 12 and 14 are drawn toward one another by an adjustableattachment assembly 56. Attachment assembly 56 joins the second end 58of the first segment 12 to the second end 60 of the second segment 14.Attachment assembly 56 is adapted to draw the segments 12 and 14 towardone another and into engagement with the pipe elements as describedbelow. In this example the adjustable attachment assembly 56 comprises afirst lug 62 attached to the second end 58 of the first segment 12, anda second lug 64 attached to the second end 60 of the second segment 14.Each lug 62, 64 defines a respective hole 66, 68 which receive afastener 70 that extends between the lugs. In this example fastener 70comprises a bolt 72 and a nut 74, which, when tightened, draw thesegments 12 and 14 toward one another against the biasing force of thespring assembly 18.

As shown in cross section in FIG. 3, each segment 12 and 14 comprisesfirst and second channels 76 and 78 respectively positioned on oppositesides 80 and 82 of each segment. The first and second channels 76 and 78extend between the first and second ends 20 and 58 of the first segment12, and the first and second ends 22 and 60 of the second segment 14(see also FIG. 1). Channels 76 and 78 face the central space 16. Asshown in detail in FIG. 4, each channel 76, 78 (channel 78 in segment 14being shown) is defined by sidewalls 84 and 86 positioned in spacedrelation to one another. Each channel 76, 78 furthermore has first andsecond floors 88 and 90 located between sidewalls 84 and 86. Floors 88and 90 face the central space 16 and are arcuate in shape as they extendbetween the ends 20 and 58 and 22 and 60 of the segments 12 and 14. Asshown in FIG. 4, first floor 88 is positioned closer to the side 82 ofsegment 14 and has a greater radius of curvature 92 than the secondfloor 90, which has a radius of curvature 94. As shown in FIG. 3, thechannels 76 and 78 and the arrangement of their floors 88 and 90 aresymmetric about an axis 96 extending transversely through the coupling10.

As further shown in FIGS. 3 and 4, the channels 76 and 78 each receive arespective retainer 98. Retainer 98 is shown in detail in FIG. 5 andcomprises an arcuate band 100 having oppositely disposed ends 102 and104. Band 100 thus forms a “split ring” which, when compressed radiallywill deform to a smaller radius of curvature (see FIG. 7). In someembodiments, each band 100 is sized such that contact between bands 100and the respective segments 12 and 14 within channels 76 and 78 allowone or both bands 100 to support segments 12 and 14 in spaced apartrelation as shown in FIG. 1. A plurality of teeth 106 are positionedalong one edge 108 of band 78. Teeth 106 project from band 100 towardthe central space 16. As shown in FIGS. 3 and 4, teeth 106 are orientedangularly toward axis 96 with respect to a line 110 extending radiallyfrom an axis 112 arranged coaxially with the central space 16. Theangular orientation is advantageous for retaining pipe elements asdescribed below.

As shown in FIG. 5, at least one, but in this example embodiment, aplurality of tabs 114 are positioned along an edge 116 oppositelydisposed from edge 108. As shown in FIG. 4, the one or more tabs 114 areoriented substantially perpendicular to the line 110 and are offset fromthe band 100 toward axis 112 arranged coaxially with the central space16. This offset of tabs 114 permits them to overlie the second floor 90,and the band 100 to overlie the first floor 88, when retainers 98 areproperly received within respective channels 76 and 78 as shown in FIGS.3 and 4. Proper assembly of the retainers 98 within the channels 76 and78 permits pipe elements to be inserted into a pre-assembled coupling 10as described below. However, as shown in FIG. 6, the channels 76 and 78(78 shown) and the retainers 98 are sized such that if the coupling 10is improperly assembled with the band 100 overlying the second floor 90and the tab or tabs 114 overlying the first floor 88, the retainer'sradius of curvature is smaller and teeth 106 effectively preventinsertion of the pipe element into the central space 16 with thesegments 12 and 14 in spaced apart relation in the pre-assembled state.This cooperation between the retainer 98, its tabs 114, teeth 106, andthe first and second floors 88 and 90 of channels 76 and 78 preventimproper assembly of a pipe joint using coupling 10. If the pipeelements could be inserted with the retainer teeth 106 facing in thewrong direction (FIG. 6) then the teeth will not be self-actuatingagainst forces which would draw or push the pipe element out of thecoupling. Thus the retainer would provide reduced mechanical restraint.

As shown in FIG. 3, segments 12 and 14 further comprise a third channel118. Channel 118 is positioned between the first and second channels 76and 78 and faces the central space 16. Channel 118 receives a ring seal120 which ensures a fluid tight joint. Ring seal 120 is formed of aflexible, resilient material such as EPDM or other rubber compounds andhas inner surfaces 122 sized to receive pipe elements when they areinserted into the central space 16 as described below. A pipe stop 124is positioned between inner surfaces 122. The pipe stop projects intothe central space 16 and limits insertion of pipe elements by engagingthe pipe elements when they are inserted into coupling 10 to the desireddepth. Ring seal 120 also has an outer surface 126 that may be sized toengage and support the segments 12 and 14 in spaced apart relation asshown in FIGS. 1 and 3. One or more of the bands 100 may also cooperatewith the ring seal 120 to support the segments 12 and 14 in spaced apartrelation. The separation of the segments 12 and 14, when supported bythe ring seal 120 and/or band or bands 100, is sufficient to permit pipeelements to be inserted into the coupling when it is in itspre-assembled state (FIGS. 1, 2 and 3). FIG. 3 shows an example channelconfiguration wherein the second floors 90 are positioned between thefirst floors 88 and the third channel 118. In this example the tabs 114project toward the third channel 118 when the retainers 98 are properlyoriented within the coupling 10.

As shown in FIG. 1, coupling 10 further comprises a first aperture 128in segment 12. In this example embodiment aperture 128 is aligned withthe first channel 76 and provides a line of sight 130 toward the centralspace 16. In this example embodiment, aperture 128 is positioned at theinterface 132 between segments 12 and 14 and is formed as a trough 134in both segments 12 and 14. The troughs 134 in each of the segments 12and 14 are aligned so that when the segments are drawn into engagementthey provide a view toward the central space 16 to permit visualconfirmation that the retainer is present and that a pipe element ispresent within the central space and seated at least past the retainer.As shown in FIG. 1A, a second aperture 136 is also positioned in atleast one of the segments 12 and 14. The second aperture 136 is alignedwith the second channel 78 in this embodiment (see FIG. 3) and alsoprovides a line of sight toward central space 16. Again, in the exampleembodiment 10 illustrated, the second aperture 136 is positioned betweenthe segments 12 and 14. Aperture 136 is also formed by troughs 134 atthe interface 132 between the segments 12 and 14. The second aperturealso permits visual confirmation that a pipe element is present withinthe central space 16.

As shown in FIGS. 1 and 3, each segment 12 and 14 also comprises firstand second arcuate surfaces 138 and 140 respectively positioned onsidewalls 84 and 86. Arcuate surfaces 138 and 140 face the central space16 and a plurality of projections 142 may be positioned on each arcuatesurface 138, 140. Projections 142 are arranged in spaced relation to oneanother along the arcuate surfaces 138 and 140 and project toward thecentral space 16. As described below, projections 142 engage the pipeelements and increase joint stiffness and accommodate a wider tolerancerange on the pipe outer diameter.

When projections 142 are forced into engagement with the pipe elementsas the segments 12 and 14 are drawn toward one another they addstiffness to the joint between the coupling 10 and the pipe elementsupon their engagement with the outer surfaces of the pipe elements.Additionally, the projections 142 allow the coupling 10 to accommodate alarger pipe outer diameter tolerance in combination with knownmanufacturing tolerances for coupling 10. When the outer diameter ofpipe elements is near the small end of the tolerance range the presenceof the projections 142 ensures mechanical engagement between thecoupling 10 and the pipe elements. However, when the pipe diameter is atthe large end of the tolerance range the projections will tend to deformthe outer surface of the pipe elements locally, and projections 142 mayalso deform. For couplings 10 used with plain end pipe elements this isparticularly advantageous as plain end couplings are typically designedso that the arcuate surfaces 138, 140 (see FIG. 3) do not engage theouter surfaces of the pipe elements. This arrangement ensures that theclamping force provided by the fastener 70 (see FIG. 2) is fully appliedto the retainers 98. Were the arcuate surfaces 138, 140 of the coupling10 to engage the pipe outer surface directly, the clamping force wouldbe divided between contact of the arcuate surfaces with the pipe andcontact between the retainers 98 and the pipe elements. Because thesurface areas of projections 142 are small relative to the arcuatesurfaces 138, 140, and contact the pipe element outer surface only atdiscrete points, only minimal clamping force from the fastener 70 needsto be diverted into contact between the projections 142 and the pipeelements to provide enhanced stiffness without compromising the axialretention provided by the retainers 98. Projections 142 are advantageousin that they achieve greater rigidity even with the lesser clampingforce available with the single fastener design of the coupling 10. Thesingle fastener 70 acts in conjunction with the spring assembly 18 toensure that adequate clamping force is applied to the pipe elements.

Operation of coupling 10 is illustrated in FIGS. 1, 3, 7 and 8. With thecoupling 10 in the pre-assembled state as shown in FIGS. 1 and 3, pipeelements 144 and 146 are inserted into the central space 16. The pipeelements clear the teeth 106 of retainers 98, engage and the innersurfaces 122 of ring seal 120, and engage the pipe stop 124. Next, thefastener 70 is tightened (see also FIG. 2) drawing the segments 12 and14 toward one another. As shown in FIG. 7 the ring seal 120 and theteeth 106 are compressed between the segments 12 and 14 and the pipeelements 144 and 146. Pivoting motion of the segments about fulcrums 28and 32 (see FIG. 2) is resisted by the biasing force of the springassembly 18. As shown in FIG. 8, the elements comprising the springassembly, in this example, the bosses 24 and 26 and the ring 44, deformin proportion to the spring force, with the ring 44 extending into anoval shape and the bosses 24 and 26 bending as cantilevers (deformedshapes shown in solid line, undeformed in broken line). Apertures 128,136 may be used to visually confirm that the pipe elements are presentin the coupling 10.

FIG. 9 shows an exploded view, and FIG. 9A shows an assembled view, of apreassembled combination coupling and pipe element 147 according to theinvention. The combination coupling and pipe element 147 comprises acoupling 148 and a first pipe element 184, and is used to couple asecond pipe element 186 to the first pipe element (see FIGS. 10 and 11).The second pipe element 186 may, for example, be part of a pipingnetwork (not shown), and the first pipe element 184 may be part ofanother assembly, such as a flexible hose for a fire suppressionsprinkler, or an inlet or and outlet of a pump or a valve to cite a fewexamples.

The coupling 148 comprises first and second segments 150 and 152positioned end to end surrounding a central space 154 for receiving pipeelements. A spring assembly 156 and an adjustable attachment assembly158, as described above for coupling 10, join the ends of the segments.Coupling 148 further comprises first and second shoulders 160 and 162(see also FIG. 10) positioned on opposite sides 164, 166 of each segment150 and 152. Shoulders 160 and 162 extend lengthwise along the segments150 and 152 and project toward the central space 154. Shoulders 160 and162 define a channel 168 which extends between the ends of the segments150 and 152 and faces central space 154. Channel 168 receives a ringseal 170 for a fluid tight joint. Ring seal 170 has an inner surface 172sized to receive pipe elements (see also FIG. 10) and an outer surface174 which may be sized to support the segments 150 and 152 in thepreassembled state, i.e., in spaced relation sufficient to insert thesecond pipe element 186 into the central space 154 without disassemblingthe combination 147. FIG. 9A shows the coupling in the preassembledstate with the segments 150 and 152 in spaced relation. As describedabove for coupling 10, the spring assembly 156 may also be used to biasthe segments 150 and 152 into the open, preassembled state shown in FIG.9A. Ring seal 170 may also comprise a pipe stop 176 positioned betweenthe inner surfaces 172. Pipe elements inserted into the central spaceengage the pipe stop 176 when properly seated (see FIG. 11).

As shown in FIGS. 9 and 10, each segment 150 and 152 further comprises afirst arcuate surface 178 positioned on the first shoulder 160 and asecond arcuate surface 180 positioned on the second shoulder 162.Arcuate surfaces 178 and 180 face the central space 154. A plurality ofprojections 182 may be positioned on the arcuate surfaces 178 and 180.Projections 182 are arranged in spaced relation to one another along thearcuate surfaces 178 and 180 and project toward the central space 154.Projections 182 engage the pipe elements and increase joint stiffnessand accommodate a wider tolerance range on the pipe outer diameter. Asshown in FIG. 9A, the coupling 148 may have at least one aperture 171 inone of the segments 150, 152. In this example the aperture 171 comprisesa trough 173 positioned at an interface between the first and secondsegments 150 and 152.

As shown in FIG. 9, the first pipe element 184 comprises a rim 188 whichprojects outwardly from the first pipe element and extendscircumferentially around. Rim 188 is positioned in spaced relation to anend 190 of the first pipe element 184, and as shown in FIGS. 9A and 10,is captured within the central space 154 by engagement with the shoulder162. Rim 188 may be defined by a circumferential groove 192 in the firstpipe element 184, or a circumferential bead 194 which projects radiallyoutwardly from the first pipe element 184. In the example embodimentshown in FIG. 9, the rim 188 is defined by both the groove 192 and thebead 194.

The preassembled combination coupling and pipe element 147 shown in FIG.9A in its preassembled state is assembled as illustrated in FIGS. 9B and9C. The first pipe element 184 is engaged with the ring seal 170. Thering seal 170 is then positioned within the channel 168 of the firstsegment 150 while the rim 188 is engaged with the first shoulder 160within what will become the central space 154. Next the spring assembly156 is formed by engaging the first end 175 of the first segment 150with the first end 177 of the second segment 152. In the example shown,engagement of the first ends 175 and 177 is effected by joining a firstboss 179 projecting from the first end 175 of the first segment 150 witha second boss 181 projecting from the first end 177 of the secondsegment 152 and pivotably linking them together using a link 183. Inthis example the link 183 comprises a ring 185 into which the bosses 179and 181 are inserted, each boss having a respective head 187, 189 whichretain the bosses within the ring 185 when the segments are pivoted intothe preassembled state. As shown in FIG. 9C, the second boss 181 iscontacted by a fulcrum 191 on the first boss 179, and the first boss 179is contacted by a fulcrum 193 on the second boss 181. The bosses 179 and181 joined by the ring 185 act as cantilever springs which bias thesegments 150 and 152 away from one another and can also be used tosupport the segments in spaced apart relation, either alone or incombination with the ring seal 170 as described above. Next the secondend 195 of the first segment 150 is attached to the second end 197 ofthe second segment 152 using the adjustable attachment assembly 158. Inthis example embodiment the adjustable attachment assembly comprises afirst lug 201 mounted on the second end 195 of the first segment 150, asecond lug 203 mounted on the second end 197 of the second segment 152,and a fastener 205 extending between the first and second lugs.

Working together with the spring assembly 156 (and/or the ring seal170), initial tightening of the fastener 205 holds the segments 150 and152 in the preassembled state shown in FIGS. 9A and 9C. In thisconfiguration the segments 150, 152 are supported in spaced apartrelation sufficient to permit the second pipe element 186 to be insertedinto the central space 154 (see FIGS. 10-11) while also capturing thefirst pipe element 184 by engagement between the shoulder 160 and therim 188. As shown in FIG. 9C, the projections 182 increase the abilityof the segments 150, 152 to retain the first pipe element 184 when thecombination 147 is in the preassembled state.

FIGS. 10 and 11 illustrate use of the combination 147 to join pipeelements 184 and 186. As shown in FIG. 10, with the combination 147 inthe preassembled state the second pipe element 186 is inserted into thecentral space 154. Upon insertion the second pipe element 186 engageswith surface 172 on the ring seal 170 (the first pipe element 184 issimilarly engaged with the ring seal). As shown in FIG. 11, the segmentsare then drawn toward one another using the adjustable attachmentassembly 158. In this example the fastener 205 is tightened, drawing thesegments 150 and 152 against the biasing force of the spring assembly156 (see FIG. 9C) and compressing the ring seal 170 to form a fluidtight joint. If projections 182 are present they engage the pipeelements 184, 186, otherwise, the arcuate surfaces 178 and 180 engagethe pipe elements. FIG. 11 shows the arcuate surface 178 engaging agroove 192 in the second pipe element 186.

FIG. 12 shows an embodiment of the preassembled combination 147 whereinthe first arcuate surface 178 has a first radius of curvature 207 andthe second arcuate surface 180 has a second radius of curvature 209. Inthis example embodiment the second radius of curvature 209 is less thanthe first radius of curvature 207. This configuration of radii isappropriate when rim 188 of the first pipe element is defined by agroove 192 because it permits the first pipe element 184 to be capturedby coupling 148 when it is in the preassembled state, while allowing thesecond pipe element 186 to be inserted into the central space 154without disassembling the coupling. The groove 192 in the first pipeelement 184 may be deeper than the groove 192 in the second pipe element186 to accommodate this embodiment.

The use of the combination 147 having a single fastener 205 and acaptured pipe element 184 provides significant advantage by increasingthe stability of the coupling on the pipe elements through engagementbetween the coupling shoulder and the rim of the pipe element. Thepresence of the spring assembly and single fastener significantlyinhibit the ability to manipulate the coupling by rocking it, making itmuch more difficult to separate the pipe element from the coupling. Thesingle fastener also simplifies the tightening step, as only onefastener need be tightened, as opposed to two fasteners, which must betightened in an alternating sequence to avoid damage to the ring seal.

Couplings according to the invention are expected to improve theefficiency of installation and the reliability of joints formed. Furtherexpected advantages include a lighter weight coupling which has a lowerexternal profile and which is smaller for a given pipe size. Having onlyone fastener reduces the part count and contributes to reduced errorsduring assembly, as well as eliminating the need to tighten more thanone fastener in an alternating sequence.

What is claimed is:
 1. A preassembled combination for connecting acaptured pipe element to a second pipe element, the captured pipeelement defining an axis, the combination comprising: a couplingassembly comprising first and second segments connected end to end suchthat first and second ends of the first segment are connected to firstand second ends, respectively, of the second segment, such that thefirst and second segments surround a central space for axially receivingsaid second pipe element, wherein said first and second segments areshaped and configured to be drawn toward one another and into engagementwith said pipe elements, first and second shoulders positioned onopposite sides of each of said segments, said shoulders of the segmentsextending along said segments and projecting radially-inwardly towardsaid central space, a first arcuate surface positioned on and extendingalong each of said first shoulders, said first arcuate surface havingtwo ends and a midpoint therebetween, a second arcuate surfacepositioned on and extending along each of said second shoulders, of thefirst and second arcuate surfaces facing said central space, a channelpositioned between said first and second shoulders in each of saidsegments, said channels extending between said ends of said segments andfacing said central space, and an annular ring seal positioned withinsaid channels, said ring seal having inner surfaces sized to receivesaid pipe elements, said ring seal supporting said segments in spacedapart relation sufficient to permit insertion of said second pipeelement into said central space while said segments are attached to oneanother; and the captured pipe element, wherein the captured pipeelement comprises an annular body, said annular body having an end facelocated within said central space, a sealing surface extending aroundsaid captured pipe element for engagement with the said inner surface ofsaid ring seal, a bead projecting outwardly from said sealing surfaceand extending circumferentially therearound, a groove axially spacedfrom said end face, said groove for engagement with said first arcuatesurfaces of the first shoulders of the segments, and a pipe shoulderpositioned distal from said end face and adjacent to said groove,wherein said end face of said captured pipe element is retained withinthe central space by engagement between said bead and said couplingassembly.
 2. The combination according to claim 1, wherein said end faceof said captured pipe element is retained within the central space byengagement between one of said bead and said pipe shoulder with saidcoupling assembly.
 3. The combination according to claim 1, wherein saidbead is positioned in spaced relation to an end of said captured pipeelement.
 4. The combination according to claim 1, wherein said sealingsurface is positioned between said end and said bead.
 5. The combinationaccording to claim 1, wherein said coupling comprises an adjustableattachment assembly adapted to draw said first and second segmentstoward one another and into engagement with said pipe elements, whereinsaid adjustable attachment assembly comprises: a first lug attached tosaid second end of said first segment; a second lug attached to saidsecond end of said second segment and positioned in facing relation withsaid first lug, each said lug defining a respective hole; a fastenerextending between said first and second lugs, said fastener beingreceived within said respective holes, said fastener being adjustablefor drawing said segments toward one another.
 6. The combinationaccording to claim 1, wherein: said inner surfaces of said annular ringseal have an innermost extent located at a first radial distance fromsaid axis when undeformed; said segments are supported such that saidmidpoints of said first arcuate surfaces are supported at a secondradial distance from said axis; an outermost portion of said bead islocated a third radial distance from said axis; and said third radialdistance is greater than said first radial distance.
 7. The combinationaccording to claim 1, wherein: said inner surfaces of said annular ringseal have an innermost extent located at a first radial distance fromsaid axis when undeformed; said segments are supported such that saidmidpoints of said first arcuate surfaces are supported at a secondradial distance from said axis; and said third radial distance of saidbead is greater than said second radial distance of said midpoint ofsaid first arcuate surfaces.
 8. The combination according to claim 1,where said bead is engaged with said ring seal.
 9. The combinationaccording to claim 8, where engagement between said bead and said ringseal creates interference that impedes movement of said captured pipeelement in a first direction along said axis of said ring seal.
 10. Thecombination according to claim 9, where interference between said pipeshoulder and said coupling acts to limit movement of said captured pipeelement along said axis of said ring seal.
 11. The combination accordingto claim 1, where said captured pipe element is retained within saidcentral space such that said first shoulder of said coupling assembly islocated axially between said pipe shoulder and said bead.
 12. A firstpipe element shaped and configured for engagement with a coupling forjoining together the first pipe element and a second pipe element,wherein the coupling comprises a plurality of segments attached to oneanother end to end to form a loop around a central space, each of saidsegments comprising a first shoulder, a second shoulder, and a channeldisposed between the first and second shoulders and facing the centralspace, wherein the first and second shoulder project radially-inwardlytoward the central space, and a flexible, resilient ring seal positionedin said channels, the ring seal comprising first and second lobes thateach extend radially inwardly to define first and second ring inner sealsurfaces, respectively, the first pipe element comprising: a first end;a circumferentially extending sealing surface; an annular groove; a pipeshoulder extending radially-outwardly; and a bead extendingradially-outwardly, wherein the bead, annular groove, and sealingsurface are all axially disposed between the first end and the pipeshoulder, wherein the bead and sealing surface are both axially disposedbetween the annular groove and the first end, wherein the first pipeelement is shaped and configured to be preassembled with the coupling toform a preassembled combination in which (1) the first end and pipeshoulder are positioned within the central space, (2) the coupling ispreassembled such that its segments are attached to one another end toend to form the loop around the central space, (3) the bead extendsradially outwardly farther than an inner radial extent of the firstlobe, (4) the coupling and bead are shaped and positioned such that thefirst and bead are captured within the central space such that the firstpipe element is captured by the preassembled coupling, (5) the secondshoulders of the plurality of segments are axially disposed between thebead and pipe shoulder and are axially aligned with the annular groove,and (6) an end of the second pipe element may be axially inserted intothe central space, wherein the first pipe element is shaped andconfigured such that when the first pipe element and coupling form thepreassembled combination and the end of the second pipe element isproperly inserted into the central space, the plurality of segments canbe drawn toward one another and the central space and to thereby cause(1) the first ring inner seal surface to sealingly engage the sealingsurface of the first pipe element, (2) the second ring inner sealsurface to sealingly engage a sealing surface of the second pipeelement, (3) the second shoulders of the segments to engage the grooveof the first pipe element, and (4) the first shoulders of the segmentsto engage an annular groove of the second pipe element, thereby joiningthe second pipe element with the first pipe element.
 13. The first pipeelement of claim 12, in combination with the ring seal, wherein: thefirst end and bead of the first pipe element are disposed within acentral opening formed by the ring seal, the bead extends radiallyoutwardly farther than an inner radial extent of the first lobe andengages the first lobe, the engagement between the bead and the firstlobe creates interference that impedes axial movement of the ring sealrelative to the first pipe element in a first axial direction.